2021/07/16 by Andrea Medini, Medini, Andrea, Zoltán Vidnyánszky +1
Mathematics · #03E15 #03E60 #54H05 #Advanced Banach Space Theory #Advanced Topology and Set Theory #FOS: Mathematics #General Topology (math.GN) #Homotopy and Cohomology in Algebraic Topology #Logic (math.LO) #Rings, Modules, and Algebras
paper · pdf · doi:10.48550/arxiv.2107.07747
openalex publication_date 2021/07/16 · openalex created_date 2023/07/19 · openalex updated_date 2026/07/28
All spaces are assumed to be separable and metrizable. Ostrovsky showed that every zero-dimensional Borel space is σ-homogeneous. Inspired by this theorem, we obtain the following results: assuming AD, every zero-dimensional space is σ-homogeneous; assuming AC, there exists a zero-dimensional space that is not σ-homogeneous; assuming V=L, there exists a coanalytic zero-dimensional space that is not σ-homogeneous. Along the way, we introduce two notions of hereditary rigidity, and give alternative proofs of results of van Engelen, Miller and Steel. It is an open problem whether every analytic zero-dimensional space is σ-homogeneous.